CMOS电压模式伪指数功能电路

CMOS Voltage-Mode Pseudo-Exponential Function Circuit

根据函数(1+x)/(1-x),利用MOS晶体管工作在饱和区的平方律特性,设计了一种电压模式的CMOS伪指数功能电路.该指数电路由一对简单的背对背电流镜和一个电流模式的除法器构成.基于TSMC 0.18μm CMOS工艺,3.3 V工作电压下的Hspice仿真结果显示电路的输出电压与输入电压之间成良好的指数关系即dB-线性关系.在dB-线性内,输出电压的动态范围为20 dB,误差在1 dB之内.

A CMOS voltage-mode pseudo-exponential circuit based on the function （1 ＋x）/（1-x） is realized by using MOS transistor square law in saturation region. The circuit consists of a couple of simple back to back current mirror and a current-mode divider. Based on the TSMC 0. 18μm CMOS process, 3. 3 V power supply, simulation results using Hspice show that the output voltage and the input voltage manifest a good dB-linear relation, and the dB-linear range of the output voltage within the error of less than 1 dB is 20 dB.